Prior methods of repairing damaged pipe lines include moving a liner tube impregnated with a liquid material capable of curing and hardening to the position within the pipe where the damaged portion is located. The liner tube is urged in an outward radial direction into contact with the pipe line being repaired and the liquid material impregnating the liner tube is permitted to cure and harden. The liner tube forms an interior liner in the pipe for the pipe line being repaired.
On some occasions, lateral pipe lines are connected to main pipe lines. Often damage occurs at the junction between the lateral pipe line and the main pipe line. T-shaped or Y-shaped liner tubes have been utilized to fit within the junction between the lateral pipe line and the main pipe line. Liner tubes form a T-shaped or Y-shaped liner after hardening to the interior of the junction between the lateral pipe line and the main pipe line. However, the liner tube may not extend far enough into the lateral pipe to complete the repair, and therefore it is necessary to add a second liner to fully repair the lateral pipe. Here, it is necessary to overlap a second liner with the first liner to cover the entire section of damaged pipe.
In other instances, the original pipe becomes damaged after a first pipe liner has been installed. In order to cover the damaged area, a new pipe liner must be installed. This new pipe liner may be inserted so that it overlaps with the original pipe liner, ensuring that the entire damaged area is covered to help avoid the potential for groundwater leaks.
One problem with the methods described above is that the liners are generally not a single unit, and therefore will not bind together. Further, there may be a plastic coating as well as fats, oils, or grease on the first liner, further limiting the ability of the two liners to bind together. In the event that there is any binding, such binding will merely be surface binding, and will be subject to creep, expansion and contraction, and shrinkage between the thermoset resins. One further problem with the current methods is that ground water outside the lateral pipe line and the main pipe line infiltrates through the damaged portion of the pipe line and migrates in the interface between the two liners to a point where it can enter the pipe line.
Therefore, a primary object of the present invention is the provision of an improved method for repairing pipe using multiple pipe liners.
A further object of the present invention is the provision of a method for repairing a pipe where a damaged portion of the pipe extends further than a single liner.
A further object of the present invention is the provision of a method for repairing damaged pipe extending from where a first pipe liner that has already been installed in the host pipe is positioned.
A further object of the present invention is the provision of a method for repairing pipe using a compressible seal between a first pipe liner and a second pipe liner.
A further object is the provision of a method for repairing pipe using a hydrophilic or hydrophobic material between two liners that expands to provide a water tight seal between first and second overlapping liners.